Conventionally, a technique has been studied of wirelessly transmitting power from a power transmission apparatus to a power reception apparatus. For example, as such a radio power transmission system, a magnetic resonance manner has been devised. Specifically, by adjusting a drive frequency of each resonator so that a resonator of the power transmission apparatus and a resonator of the power reception apparatus resonate with each other at a specific frequency, power is wirelessly transmitted from the power transmission apparatus to the power reception apparatus (for example, Patent Literature 1).
It is considered that the power transmission apparatus does not grasp the power reception apparatus existing around the power transmission apparatus. Alternatively, it is considered that the power transmission apparatus does not grasp the power reception apparatus operating even when grasping the power reception apparatus existing around the power transmission apparatus. Alternatively, it is considered that the power transmission apparatus does not grasp the power reception apparatus newly installed.
Therefore, it is preferable that the power transmission apparatus transmits a search signal for searching a power transmission target power reception apparatus, and detects the power transmission target power reception apparatus by information transmitted from the power reception apparatus.
However, when the power reception apparatus does not have a power storage unit such as a capacitor and a secondary battery, the power reception apparatus is not able to transmit the information if the power is not transmitted from the power transmission apparatus. In addition, when the power stored in the power storage unit is not able to provide power necessary for communication even if the power reception apparatus has the power storage unit such as the capacitor and the secondary battery, the power reception apparatus is not able to transmit the information if the power is not transmitted from the power transmission apparatus.
In this way, due to power shortage of the power reception apparatus, there is a case where the power reception apparatus is not able to communicate, and the power transmission target power reception apparatus may not be detected.